The present invention provides a nitrogen-free ARC layer, which is formed on the basis of silane and carbon dioxide by PECVD in a nitrogen-free deposition atmosphere. The optical characteristics may be tuned in a wide range, wherein, in particular, a back reflection into the resist is maintained at 3% or less. The ARC layer is well suited for 193 nm lithography.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method, comprising: determining a target value for at least one optical characteristic for an ARC layer to be formed above an interlayer dielectric of a metallization layer, such that a bottom reflectivity of a resist layer formed on said ARC layer is approximately 3% or less; and depositing said ARC layer in a substantially nitrogen-free atmosphere on the basis of silicon and carbon containing precursors above said interlayer dielectric while controlling at least one process parameter on the basis of said target value, wherein said at least one process parameter comprises a ratio of said silicon containing precursor and said carbon containing precursor in the range of approximately 0.012 to 0.020.
2. The method of claim 1 , wherein said substantially nitrogen-free atmosphere includes a plasma.
3. The method of claim 1 , wherein said precursors comprise silane.
4. The method of claim 3 , wherein said precursors comprise carbon dioxide gas.
5. The method of claim 1 , wherein said target value for said at least one optical characteristic is selected for an exposure wavelength of approximately 193 nm.
6. The method of claim 1 , wherein said target value for said at least one optical characteristic represents an extinction coefficient that is within a range of approximately 0.35 to 0.95.
7. The method of claim 1 , wherein said target value for said at least one optical characteristic represents an index of refraction that is within a range of approximately 1.72 to 2.12.
8. The method of claim 1 , wherein depositing said ARC layer is controlled to obtain a layer thickness in the range of approximately 50-150 nm.
9. The method of claim 8 , wherein a layer thickness of said ARC layer is approximately 60±6 nm.
10. The method of claim 8 , wherein a layer thickness of said ARC layer is approximately 70 nm.
11. The method of claim 8 , wherein a layer thickness of said ARC layer is approximately 120 nm.
12. The method of claim 1 , wherein a flow rate of said carbon containing precursor is approximately 5000 sccm or less.
13. The method of claim 1 , wherein a pressure in said nitrogen-free atmosphere is in the range of approximately 6.0 to 6.6 Torr.
14. The method of claim 1 , wherein a temperature of a substrate having formed thereon said interlayer dielectric is in the range of approximately 300-430° C. during the deposition of said ARC layer.
15. The method of claim 1 , wherein a temperature of a substrate having formed thereon said interlayer dielectric is in the range of approximately 350-400° C. during the deposition of said ARC layer.
16. A method of forming a substantially nitrogen-free ARC layer, the method comprising: creating a deposition atmosphere on the basis of a silicon containing precursor, carbon dioxide and a nitrogen-free carrier gas, wherein a ratio of said silicon containing precursor and the carbon dioxide is in the range of approximately 0.012 to 0.020; generating a plasma in said deposition atmosphere; and depositing at least silicon, oxygen and carbon on a substrate to form said substantially nitrogen-free ARC layer, wherein target values for an index of refraction, an extinction coefficient and a layer thickness of said ARC layer are selected to obtain a back reflection from a bottom surface of a resist layer formed on said substantially nitrogen-free ARC layer that is 3% or less for an exposure wavelength of approximately 193 nm.
17. The method of claim 16 , further comprising determining a target value of at least one optical characteristic of said substantially nitrogen-free ARC layer and controlling at least one deposition parameter on the basis of said target value.
18. The method of claim 17 , wherein said target value for said at least one optical characteristic is determined for an exposure wavelength of a subsequent lithography of approximately 193 nm.
19. The method of claim 16 , further comprising forming an interlayer dielectric for a metallization layer prior to depositing said substantially nitrogen-free ARC layer.
20. The method of claim 19 , wherein forming said interlayer dielectric includes forming a capping layer on a top surface of said interlayer dielectric.
21. The method of claim 20 , wherein said capping layer is formed on the basis of nitrogen-free precursors.
22. The method of claim 19 , wherein said metallization layer is the first one of a plurality of metallization layers to be formed.
23. The method of claim 16 , wherein a flow rate of said carbon dioxide is approximately 5000 sccm or less.
24. The method of claim 16 , wherein a pressure in said deposition atmosphere is in the range of approximately 6.0 to 6.6 Torr.
25. The method of claim 16 , wherein a temperature of said substrate is in the range of approximately 300-430° C. during the deposition of said ARC layer.
26. The method of claim 16 , wherein a temperature of said substrate is in the range of approximately 350-400° C. during the deposition of said ARC layer.
27. The method of claim 16 , wherein at least one of high frequency energy for generating said plasma, a substrate temperature, a pressure in said deposition atmosphere and a flow rate of gases supplied to said deposition atmosphere is selected to obtain a deposition rate in the range of approximately 100-140 nm per minute.
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January 13, 2005
February 5, 2008
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